Routes of yolk utilisation in the newly‐hatched chick

1. This study was conducted to study the routes by which yolk is utilised in the chick during the initial posthatch phase.

2. Transfer from yolk to blood was examined by injecting, in the form of labelled compounds, oleic acid, triolein, inulin and dextran into the yolk; movement from yolk to blood was observed up to 72 h posthatch.

3. Transport of these molecules from blood to yolk was also observed by injecting them into the circulation and determining label in yolk. The yolk sac membrane was permeable in both directions for all labelled materials tested.

4. In the newly‐hatched chick, blue dextran injected into the yolk sac could be seen moving in pulses into the intestine at irregular intervals. Transport of labelled materials from the yolk sac into the intestine was observed up to 72 h after hatching, and marker was found in the proximal small intestine and gizzard. The yolk stalk provided a pathway for transport to the intestine until lymphoid cells began to accumulate, with passage becoming partially occluded at 72 h posthatch.

5. Yolk utilisation was more rapid in fed than in fasted birds suggesting that the transport of yolk through the intestine could be increased by the greater intestinal activity found in fed chicks.     

Supplementation of groundnut‐based broiler chick diets with pyridoxine

1. Broiler chicks fed on a semi‐purified diet containing 230 g crude protein and less than 5 mg pyridoxine/kg had poor growth rates and high mortality.

2. When a milled, unsupplemented diet based on rice and groundnut was fed, food utilisation, carcass fat content and serum aspartate amino transferase [EG 2.6.1.1] activity indicated the need for supplementation with at least 3 mg pyridoxine, or a total concentration of 8.8 mg/kg diet.

3. With a maize‐groundnut diet body‐weight gain, food intake and tissue aspartate aminotransferase activities suggested that dietary supplementation with pyridoxine was unnecessary, but food utilisation indicated a need for supplementation with 3 mg or a total intake of 9 mg pyridoxine/ kg diet.

4. A practical broiler chick starter diet was used to show that the total concentration of pyridoxine should be at least 7.2 mg/kg when maize‐groundnut diets are fed.     

Studies on the toxic effects of crambe meal and two of its constituents, 1‐cyano‐2‐hydroxy‐3‐butene (GHB) and epiprogoitrin,in broiler chick diets

1. Studies were undertaken to determine a safe inclusion rate for crambe (Crambe abyssinica) meal in broiler chick diets, and to determine the mechanism for adverse effects by investigating its constituents; l‐cyano‐2‐hydroxy‐3‐butene (CHB) and 3‐butenyl glucosinolate (epi‐progoitrin, E‐PG).

2. Crambe meals were prepared to differ in E‐PG (19, 36 and 40 g/kg) and CHB contents (0.1, 0.7 and 1.9 g/kg), and with either active or inactive thioglucosidase.

3. Meals were fed to 7‐d‐old broiler chicks at 50 or 100 g/kg of the diet for 12 or 13 d. In separate studies, isolated E‐PG or CHB were mixed into the diet or administered by gavage to 7‐d‐old broiler chicks in amounts equivalent to 50 or 100 g/kg crambe meal diets for 10 and 12 d, respectively.

4. Weight gain decreased (P<0.05) in chicks fed on the high glucosinolate crambe diets or isolated E‐PG. Food consumption decreased (P<0.05) in chicks fed on the diet containing the high E‐PG meal with active enzyme.

5. Mild liver lesions and increased serum aspartate aminotransferase were found in chicks fed on the diet containing the high glucosinolate meal with active enzyme. Other organs, including thyroids, were normal.

6. Commercially‐processed crambe meal appeared safe at an inclusion rate of 50 or 100 g/kg diet, but could not be recommended at this point for long term feeding.     

α‐Tocopherol absorption and polyunsaturated fatty acid metabolism in the developing chick embryo

1. A study has been made relating α‐tocopherol uptake from the yolk and yolk sac membrane to the polyunsaturated fatty acid status of the liver during incubation.

2. Whereas at day 15 of incubation lipid in the liver showed an exceedingly high degree of unsaturation and potential for oxidation because of accumulation of C20 and C22 polyunsaturated fatty acids, α‐tocopherol concentrations were exceedingly low.

3. In contrast, very high concentrations of α‐tocopherol occurred within the liver just before hatching by which time amounts of polyunsaturates and the need for oxidation protection had reduced considerably.     

Some observations on the caecal micro‐flora of the chick during the first two weeks of life

1. Changes in the caecal flora of chicks aged from approximately 3 h to 14 d were studied.

2. Counts obtained by means of a conventional anaerobic plating method and a method for the stricter anaerobes remained comparable throughout but occasionally it was found that strains of anaerobic bacteria isolated from the predominant flora of 4‐ to 14‐d‐old birds could not be grown when tested by the conventional method.

3. During the 14‐d period approximately 100% of the organisms isolated on anaerobic plates utilised uric acid up to the third day but the incidence subsequently declined and in one case represented only 4% of the total flora.

4. The predominant uric acid‐utilising bacteria were Streptococcus faecalis and Escherichia coli up to 3 d of age and various types of anaerobic bacteria thereafter.

5. None of the isolates showed an absolute requirement for uric acid.     

Inheritance of the spangled plumage pattern and the marbled chick down phenotypes of the silver‐spangled Hamburgh Bantam

1. An investigation was conducted among the progeny from crosses between Silver‐Spangled and Gold‐Pencilled Hamburgh bantams, and between Silver‐Spangled Hamburgh and Double‐Laced Barnevelder bantams.

2. Two subjects were studied: the relationship between three plumage pattern phenotypes, spangling, transverse‐barring and double‐lacing, all of which are arrangements of eumelanin expressed on a background of phaeomelanic pigmentation and the inheritance of the marbled chick down of the Silver‐Spangled Hamburgh bantam.

3. Examination of the F₂ generations demonstrated that, in conjunction with silver (S) gene(s) and extended black (E) alleles at the E‐locus the silver‐spangled phenotype can be produced by the addition to the genotypes of the Gold‐Pencilled Hamburgh, homozygous e^bc (Db‐ml⁺‐Pg), and Double‐Laced Barnevelder, homozygous e^b (db⁺‐Ml‐Pg), of Sp and Db genes respectively. Consequently Sp and Ml are one and the same gene, for which I retain the symbol Ml, and the genotype of the Silver‐Spangled Hamburgh is homozygous E (Db‐Ml‐Pg), where the buttercup (e^bc) and brown (e^b) are alleles of the E‐locus and Db, Ml, Sp and Pg are respectively the eumelanin restrictor dark‐brown Columbian, the eumelanin extension melanotic, plumage pattern spangling and the pattern gene.

4. The exact correlation between S/‐ E/E Db/Db and the marbled chickdown phenotype demonstrated the latter to be a pleiotropic effect of Db/Db, thus enabling the mapping of Db, Ml and Pg in group 3 on chromosome 1.     

The role of ion transport in the formation of sub‐embryonic fluid by the embryo of the Japanese quail

1. Using a modification of the method of New (1955) explanted blastoderms of the Japanese quail were cultured for up to 72 h, and the role of ions in the formation of sub‐embryonic fluid (SEF) investigated.

2. Culture media deficient in either sodium or chloride ions reduced the volume of SEF secreted by up to a quarter. Ionic composition of the fluid was little altered, and sodium was transported against a concentration gradient.

3. Amiloride, an inhibitor of Na⁺/H⁺ exchange, reduced SEF production by half, whereas ionic composition and osmolality of the fluid was unchanged.

4. Likewise, acetazolamide, an inhibitor of carbonic anhydrase, reduced SEF production by the blastoderm, and left the ionic composition and osmolality of the fluid unaltered.

5. Neither furosemide or 4,4´‐diisothiocyanatostilbene‐2,2´‐disulfonic acid at the concentrations used changed the volume of SEF formed or its ionic composition.

6. It is concluded that the secretion of SEF is dependent upon the active transport of sodium across the blastoderm; an amiloride‐sensitive Na⁺/H⁺ exchanger and carbon dioxide hydration catalysed by carbonic anhydrase are also involved.

7. Furthermore, it is proposed that fluid transport across the blastoderm is the result of local osmotic gradients, not from a sub‐embryonic fluid hyperosmotic to albumen, as has been suggested previously.     

Evaluation of methanol‐grown bacteria and hydrocarbon‐grown yeast as sources of protein for poultry: Studies with young chicks

1. In a series of five trials, conducted with broiler chicks during the starting period, two types of dietary single‐cell protein were tested: Pruteen (PR), a protein concentrate produced from methanol‐utilising bacteria, and a Lavera‐type yeast (LA) utilising the normal paraffins of heavy gas oil.

2. The inclusion of 90 to 150 g PR or LA/kg diet depressed growth rate by 14 to 16% and 9 to 10%, respectively. This effect was slightly counteracted (about 6 percentage units) by the addition of L‐arginine.

3. The growth depression can be explained completely in the case of PR or almost completely in that of LA on the basis of reduced food intake, without a decided effect on food utilisation.

4. The reduced consumption of PR‐containing diets is not due to a petroleum‐ether‐soluble factor, nor to the high and low concentrations of sodium and potassium, respectively, in PR.     

Comparison of DL‐methionine and methionine hydroxy analogue‐free acid in broilers by using multi‐exponential regression models

1. Methionine hydroxy analogue‐free acid (MHA‐FA) was evaluated for biopotency compared to DL‐methionine in a practical diet for broiler chicks.

2. Both methionine sources were added at equimolar concentrations of 0.03, 0.07, 0.11, 0.15, 0.20 and 0.25% to the diet.

3. A non‐linear multi‐exponential regression model was used to describe the weight gain and food conversion response to supplemental sources of methionine.

4. Compared with DL‐methionine on an equimolar basis, bioefficacy of MHA‐FA was calculated at 73% from weight gain and 68% from food conversion data, respectively. This corresponds to an efficiency of Alimet® between 60 and 64% relative to DL‐methionine on a weight for weight basis.     

Identification of tissue hypoxia in the livers of ascitic and hypoxia‐induced broilers using trypan blue

1. The perfusion of livers with the vital dye trypan blue was performed to test for evidence of tissue hypoxia in 3 groups of young broiler chickens, namely, ascitic, hypoxia‐induced and controls.

2. Hepatocytes that stained with trypan blue were considered to be dead or dying before fixation and represented damaged cells.

3. The proportion of trypan blue‐stained hepatocytes in the livers of ascitic birds was slightly less than half that observed in the hypoxia‐induced birds but significandy more than the proportion of stained cells observed in control birds.

4. Liver damage in the ascitic birds was also assessed biochemically by an altered enzyme profile.

5. The study demonstrated that increased trypan blue uptake in the livers of ascitic birds reared at sea‐level may be the consequence of hypoxia stress caused by reduced oxygen utilisation.     

Derivation of feline vaccine-associated fibrosarcoma cell line and its growth on chick embryo chorioallantoic membrane – a new in vivo model for veterinary oncological studies

Feline vaccine associated fibrosarcomas are the second most common skin tumor in cats. Methods of treatment are: surgery, chemotherapy and radiotherapy. Nevertheless, the usage of cytostatics in feline vaccine associated sarcoma therapy is limited due to their adverse side effects, high toxicity and low biodistribution after i.v. injection. Therefore, much research on new therapeutic drugs is being conducted. In human medicine, the chick embryo chorioallantoic membrane (CAM) model is used as a cheap and easy to perform assay to assess new drug effectiveness in cancer treatment. Various human cell lines have different tumors growth on CAM. In veterinary medicine such model has not been described yet. In the present article derivation of feline vaccine associated fibrosarcoma cell line and its growth on CAM is described. The cell line and the tumor grown were confirmed by histopathological and immunohistochemical examination. As far as we believe, this is the first attempt to create such model, which may be used for further in vivo studies in veterinary oncology.     

The effect of a single oral dose of non‐protein nitrogen from various sources on amino acid concentrations in the plasma and liver of the chick

1. Broiler chicks were fed normally for 21 d, then starved overnight and given a single oral dose of an aqueous solution of diammonium hydrogen citrate (DAHC), triammonium citrate (TAC), ammonium lactate (AL) or urea equivalent to 24.76 mg N. Controls were given water. The concentrations of free amino acids in the plasma were measured 2, 4 or 6 h after dosing. The only non‐essential amino acid significantly affected was glutamine, which increased in chicks given DAHG or TAC

2. In another experiment, non‐protein nitrogen (NPN) from the same sources was given at dosages of 124 mg N per chick. The concentrations of free amino acids in the plasma and liver were determined 2, 4 or 6 h after dosing. NPN from all sources increased the amount of glutamic acid and glutamine in both tissues (P< 0.001), although the response to urea was delayed. The concentrations of plasma aspartic acid (P<0.05), plasma alanine (P< 0.001) and liver aspartic acid (P< 0.001) also increased.

3. The results are discussed in relation to earlier studies with liver homogenates in vitro.     

Effects associated with the pea‐comb gene on chick weight,and body weight and food efficiency of adult hens

1. Growth rate, laying traits, food intake and food conversion efficiency of laying hens were compared in several experiments on pairs of full or half sibs one of which was a pea‐comb bird (Pp), the other single‐comb (pp).

2. There was a slight but significant depressing effect associated with the Pp genotype on 8‐week weight of chicks and body weight of laying hens in some populations.

3. Pea‐comb hens showed a reduction of about 2% in food consumption, independent of the effects on body weight and egg production, and we suggest that with the smaller size of comb and wattles for Pp hens, heat losses and hence energy requirements are less.

4. Appetite seemed to be more depressed at high ambient temperature in birds of the Pp genotype.     

Effects on chick performance and nutrient digestibility of an endo‐xylanase added to a wheat‐ and rye‐based diet in relation to fat source

1. A study with growing chicks investigated the effects of an inclusion of an endo‐xylanase preparation (LYXASAN®) to a wheat‐ and rye‐based diet on performance and nutrient digestibility in relation to the fat source.

2. The basal diet contained 500 g wheat and 100 g rye/kg of diet. The basal diet was supplemented with either 65 g soya oil/kg or 60 g blended animal fat and 5 g soya oil/kg.

3. Endo‐xylanase added to the soya oil diet did not affect weight gain, but there was a numerical improvement in food conversion efficiency which was not statistically significant. When the endo‐xylanase preparation was added to the blended animal fat diet, both weight gain and food utilisation were improved by 9.5% and 6.0%, respectively (P< 0.05).

4. Digestibilities of organic matter, crude fat, crude fibre and NFE were not significantly affected by adding endo‐xylanase to the soya oil diet. However, when endo‐xylanase was included in the blended animal fat diet, digestibility of organic matter, crude fat, crude fibre and NFE were improved (P<0–05). The improvement in fat digestibility was the most pronounced, amounting to 9–4%. Nitrogen retention and metabolisable energy content were improved significantly by the addition of an endo‐xylanase to the animal fat diet (P< 0.05), by 6.6% and 6.5% respectively.

5. From the results of this study, it can be concluded that the effects on chick performance and nutrient digestibility of a dietary endo‐xylanase in a wheat‐ and rye‐based diet are influenced to a considerable degree by the type of fat in the diet.     

Antimicrobial substances and chick growth promotion: The growth‐promoting activities of antimicrobial substances,including fifty‐two used either in therapy or as dietary additives

1. Fifty‐five antimicrobial substances were tested for their ability to promote growth when added to the diet of chicks.

2. Both cephalosporins and all the nine penicillins tested were active.

3. Of six aminoglycosides, streptomycin and gentamicin had the greatest activity and neomycin had none.

4. Growth rate was significantly improved by clindamycin, lincomycin, vancomycin, spectinomycin, rifampicin, oxytetracycline, chlortetracycline, erythromycin, tylosin, flavomycin, virginiamycin and zinc bacitracin. Chloramphenicol and nalidixic acid were inactive. Polymixin B, novo‐biocin, cycloserine, phosphonomycin, and sodium fusidate had little activity. Fusidic acid promoted growth at 250 mg/kg diet.

5. Trimethoprim was inactive alone and in combination with sulpha‐diazine. Of seven 5‐nitroimidazoles, only dimetridazole and metronidazole showed slight activity. Of the six 5‐nitrofurans, only nitrovin, the standard reference substance used, promoted growth.

6. Caprylohydroxamic acid, a urease inhibitor, had no beneficial effect on growth rate or on the efficiency of food conversion.

7. The growth‐promoting properties of the various substances could not be related with their known antimicrobial and absorption characteristics in mammals.     

Utilisation of U‐14C‐lysine by young turkeys

1. U‐¹⁴C‐lysine was administered by tube into the crop to turkey poults fed on assay diets (maize + sesame + maize gluten meal) containing varying concentrations oflysine, and partition of the label into body components, carbon dioxide, and excreta was measured.

2. Deposition of ¹⁴C label into breast and heart muscles responded positively to dietary lysine concentration. There was no apparent relationship between dietary lysine intake and deposition of label into carbon dioxide or excreta.

3. Efficiency of lysine retention, above maintenance, was estimated to be 0.523 ± 0.034.

4. Turkeys exhibited variable metabolic efficiency in the use of lysine as indicated by loss of U‐¹⁴C‐lysine label to expired carbon dioxide and to excreta by individual turkeys.     

Studies on acid oils and fatty acids for chickens. III. Effect of chemical composition on metabolisable energy of by‐products of vegetable oil refining

1. Fourteen by‐products of oil refining, selected for their variability in free fatty acid and unsaponifiable contents, were analysed chemically with the objective of relating the determined ME values of the products to chemical composition by means of multiple linear regression analysis. Refined sunflower oil was included as a reference fat.

2. Twenty‐one 2‐week‐old chicks were used to determine fat digestibilities and AMEn values of diets, using the total collection method. Fats were included in a wheat‐soyabean meal diet at 100 g/kg. Multiple linear regression analysis was used to express the ME values of fats as functions of the parameters measured (moisture, gross energy, impurities, unsaponifiables, non eluted material, free fatty acid content, unsaturated: saturated ratio, peroxide value, TBA test).

3. The ME of the fat products lay in the range 12.62 to 24.35 MJ/kg, and 29.26 MJ/kg for refined sunflower oil. Free fatty acid content of the fats was shown to be a poor predictor of their ME values, whereas non eluted material (NEM) of the fat products showed a good correlation with their ME. A regression equation could be derived (R² = 0.6548; SEE = 2–0064) with the unsaturated: saturated ratio (U:S) and NEM. An ME prediction equation based on the U:S, NEM and unsaponifiable content is also proposed (R² = 0–7168; SEE= 1.9058).     

Use of the Cortisol‐to‐ACTH Ratio for Diagnosis of Primary Hypoadrenocorticism in Dogs

Background

The ACTH stimulation test is currently required for definitive diagnosis of hypoadrenocorticism. Increased cost of synthetic ACTH (cosyntropin) has prompted a search for alternative diagnostic methods.

Objective

The purpose of this study was to determine whether a cortisol‐to‐ACTH ratio (CAR) can be used to differentiate dogs with hypoadrenocorticism from normal dogs and those with nonadrenal illness.

Animals

Eight healthy dogs (H), 19 dogs with nonadrenal illness (NAI), and 15 dogs with hypoadrenocorticism (HAD).

Methods

Dogs in the HAD group were retrospectively identified from PUVTH medical records. The NAI group consisted of hospitalized dogs with clinical signs, clinicopathologic findings, or both, consistent with a diagnosis of hypoadrenocorticism, but in which hypoadrenocorticism was ruled out based on ACTH stimulation test results. Healthy dogs were recruited from hospital staff and students. Endogenous ACTH concentrations and cortisol concentrations before and after ACTH stimulation were measured in all dogs.

Results

Baseline cortisol concentration was significantly lower, and ACTH concentration was significantly higher, in the HAD group versus the H and NAI group (P < .001). However, there was overlap among groups. Cortisol‐to‐ACTH ratio was significantly lower in the HAD group versus the H and NAI groups (P < .001), and there was no overlap between the HAD group and the other 2 groups.

Conclusions and Clinical Importance

CAR can be used for definitive diagnosis of primary hypoadrenocorticism.